Sindicador de canales de noticias
Fungi and mycotoxins in silage: an overview
Alonso, Veronica Andrea; Pereyra, Carina Maricel; Keller, L. A. M.; Dalcero, Ana Maria; Rosa, C. A. R.; Chiacchiera, Stella Maris; Cavaglieri, Lilia Reneé
The present revision shows the early and current knowledge in the field of silage fungi and mycotoxins explaining the relevance of fungi and mycotoxins in silage. The problem does not end in animal disease or production losses as mycotoxins in feed can lead to the presence of their metabolic products in dairy products, which will be eventually affecting human health, mainly infants. Silage is green forage preserved by lactic fermentation under anaerobic conditions. This ecosystem maintains its quality and nutritional value depending on interactions among physical, chemical and biological agents. Forages used for ensilage are naturally in contact with yeasts and filamentous fungi, and the contamination often occurs in the field and can also occur during harvesting, transport, storage. Moreover, postharvest poor management can lead to a rapid spoilage. Studies on fungal contamination of dairy cattle feed have shown how corn silage influences the contamination degree of feed supplied to livestock. Increasing knowledge in this area will help elucidate the influence that this microbiota exerts on production and/or degradation of mycotoxins present in silage. Some of these fungi, although opportunist pathogens, are relevant epidemiologically and represent a high risk of contamination to farm workers who handle them improperly.
Fumigant toxicity of Citrus sinensis essential oil on Musca domestica L. adults in the absence and presence of a P450 inhibitor
Fumigant toxicity of Citrus sinensis essential oil on Musca domestica L. adults in the absence and presence of a P450 inhibitor
Rossi, Yanina Estefanía; Palacios, Sara Maria
Essential oils (EOs) are potential tools for controlling Musca domestica L. In a fumigant assay, M. domestica adults treated with Citrus sinensis EO (LC50 = 3.9 mg/dm3), with (4R)(+)-limonene (95.1%) being its main component, died within 15 min or less. The terpenes absorbed by the flies and their metabolites, analyzed using SPME fiber, were (4R)(+)-limonene (LC50 = 6.2 mg/dm3), α-pinene (LC50 = 11.5 mg/dm3), β-pinene (LC50 = 6.4 mg/dm3), and two new components, carveol (LC50 = 1122 mg/dm3) and carvone (LC50 = 19 mg/dm3), in a proportion of 50, 6.2, 12.5, 6.3 and 25%, respectively. Carveol and carvone were formed by oxidation of (4R)(+)-limonene mediated by cytochrome P450, as was suggested by a fumigation assay on flies previously treated with piperonyl butoxide, a P450 inhibitor. In this experiment, an increase in the toxicity of the EO and (4R)(+)-limonene was observed, as well as a lower production of carveol and carvone.
La influencia de los actores no tradicionales en los procesos decisionales de la política exterior argentina: los casos Pasteras y Pascua Lama
La influencia de los actores no tradicionales en los procesos decisionales de la política exterior argentina: los casos Pasteras y Pascua Lama; The influence of non-traditional actors in the decision making process of Argentina Foreign Policy: Pulp mills and Pascua Lama
Bueno, Maria del Pilar
El artículo se centra en determinar el nivel de influencia ejercido por los denominados actores no tradicionales en el proceso de toma de decisiones de la Política Exterior Argentina durante las gestiones de Néstor Kirchner y Cristina Fernández. Para ello estudia dos casos: la construcción de fábricas pasteras a la vera del Río Uruguay y la mina binacional Pascua Lama.
Effects of growth hormone on the ontogenetic allometry of craniofacial bones
Effects of growth hormone on the ontogenetic allometry of craniofacial bones
Gonzalez, Paula Natalia; Kristensen, Erika; Morck, Douglas W.; Boyd, Steven; Hallgrimsson; Benedikt
Organism size is controlled by interactions between genetic and environmental factors mediated by hormones with systemic and local effects. As changes in size are usually not isometric, a considerable diversity in shape can be generated through modifications in the patterns of ontogenetic allometry. In this study we evaluated the role of timing and dose of growth hormone (GH) release on growth and correlated shape changes in craniofacial bones. Using a longitudinal study design, we analyzed GH deficient mice treated with GH supplementation commencing pre- and post-puberty. We obtained 3D in vivo micro-CT images of the skull between 21 and 60 days of age and used geometric morphometrics to analyze size and shape changes among control and GH deficient treated and non-treated mice. The variable levels of circulating GH altered the size and shape of the adult skull, and influenced the cranial base, vault, and face differently. While cranial base synchondroses and facial sutures were susceptible to either the direct or indirect effect of GH supplementation, its effect was negligible on the vault. Such different responses support the role of intrinsic growth trajectories of skeletal components in controlling the modifications induced by systemic factors. Contrary to the expected, the timing of GH treatment did not have an effect on catch-up growth. GH levels also altered the ontogenetic trajectories by inducing changes in their location and extension in the shape space, indicating that differences arose before 21 days and were further accentuated by a truncation of the ontogenetic trajectories in GHD groups
Monounsaturated fatty acid aerobic synthesis in Bradyrhizobium TAL1000 peanut-nodulating is affected by temperature
Monounsaturated fatty acid aerobic synthesis in Bradyrhizobium TAL1000 peanut-nodulating is affected by temperature
Paulucci, Natalia Soledad; Medeot, Daniela Beatriz; Woelke, Mariela Rosana; Dardanelli, Marta Susana; de Lema, M. G.
Aims: The aim of this work was to clarify the mechanism of monounsaturated fatty acid (MUFA) synthesis in Bradyrhizobium TAL1000 and the effect of high temperature on this process. Methods and Results: Bradyrhizobium TAL1000 was exposed to a high growth temperature and heat shock, and fatty acid composition and synthesis were tested. To determine the presence of a possible desaturase, a gene was identify and overexpressed in Escherichia coli. The desaturase expression was detected by RT-PCR and Western blotting. In B. TAL1000, an aerobic mechanism for MUFA synthesis was detected. Desaturation was decreased by high growth temperature and by heat shock. Two hours of exposure to 37°C were required for the change in MUFA levels. A potential ∆9 desaturase gene was identified and successfully expressed in E. coli. A high growth temperature and not heat shock reduced transcript and protein desaturase levels in rhizobial strain. Conclusions: In B. TAL1000, the anaerobic MUFA biosynthetic pathway is supplemented by an aerobic mechanism mediated by desaturase and is down-regulated by temperature to maintain membrane fluidity under stressful conditions. Significance and Impact of the Study: This knowledge will be useful for developing strategies to improve a sustainable practice of this bacterium under stress and to enhance the bioprocess for the inoculants' manufacture.
Of volcanoes and insects: the impact of the Puyehue-Cordon Caulle ash-fall on populations of invasive social wasps, Vespula spp.
Of volcanoes and insects: the impact of the Puyehue-Cordon Caulle ash-fall on populations of invasive social wasps, Vespula spp.
Masciocchi, Maité; Pereira, Ana Julia; Lantschner, María Victoria; Corley, Juan Carlos
Volcanic eruptions have important effects on terrestrial ecosystems. The biotic effects of volcanic ash on insect populations vary from widespread and catastrophic to subtle and localized. Volcanic eruptions may increase insect mortality through the effects of the ash plume, and these vary by taxon or specific biological features. The Puyehue-Cordon Caulle Volcanic Complex is the most recent eruption in Patagonia. Here we explore and describe the effects of the eruption of this volcanic complex on invasive Vespula spp. populations. These wasps are very abundant social hymenoptera that have recently invaded Patagonia. We placed baited traps following the gradient of deposited ash, and revisited them once a week during February to April. No wasps were caught where ash deposition levels exceeded 3.0 cm. The number of wasps caught in sites with minimal ash deposits was similar to that of previous years. In locations where ash layers are intermediate a few wasps were observed, but only during the peak of wasp abundance. We show that Vespula spp. populations were severely affected by the ash deposition and plume, caused by this eruption. These results show catastrophic effects of ash deposition over a large area, even at great distances from the eruption epicenter. We conclude that wasp mortality explained by the volcanic eruption may reach distant areas, and cause local extinction. In areas where active volcanoes are a common, invasive insects may encounter an additional obstacle in their invasion success.
Improved chemical control of chagas disease vectors in the dry Chaco region
Improved chemical control of chagas disease vectors in the dry Chaco region
Cecere, Maria Carla; Vazquez Prokopec, Gonzalo Martin; Ceballos, Leonardo A.; Boragno, Silvana; Zárate, Joaquín E.; Kitron, Uriel; Gurtler, Ricardo Esteban
The effectiveness of two doses of suspension concentrate (SC) pyrethroid insecticides in suppressing peridomestic populations of Triatoma infestans (Klug) was evaluated in 28 rural communities located in Santiago del Estero province, northwestern Argentina, including 388 houses and 1,516 identiÞed sites. Four treatments were randomly assigned to peridomiciles within each community: 5% SC -cypermethrin at standard (S, 50 mg active ingredient [AI]/m2 ) and double dose (2S), and 2.5% SC deltamethrin at standard (D, 25 mg [AI]/m2 ) and double dose (2D). Simultaneously, we assessed the effects of both pyrethroids applied at standard doses against domestic infestations. Bug infestation at the site level was assessed by timed manual collections with a dislodging agent at baseline, 13 and 21 mo postspraying (MPS). In domiciles, D and S nearly suppressed all T. infestansinfestations up to 21MPS. In peridomestic sitesinfested beforeinterventions, multiplelogistic regression analysis showed that site-level reinfestation at 13 MPS was signiÞcantly lower for treatment 2D (1%) than for other treatments, whereas 2S (6%), D (5%), and S (14%) did not differ signiÞcantly between them. The risk of reinfestation after spraying was signiÞcantly greater in goat or pig corrals than in other peridomestic ecotopes (in which treatments did not differ signiÞcantly), and in sites infested before interventions than in uninfested sites. The application of SC deltamethrin at double dose in goat or pig corrals may suppress T. infestans foci and achieve more sustained effects in the dry Chaco.
Bioactive Compounds and Antioxidant Capacity of Camarosa and Selva Strawberries (Fragaria x ananassa Duch.)
Bioactive Compounds and Antioxidant Capacity of Camarosa and Selva Strawberries (Fragaria x ananassa Duch.)
Van de Velde, Franco; Tarola, Anna M.; Güemes, Daniel Raul; Pirovani, Maria Elida
Strawberries represent an important source of bioactive compounds due to their vitamin C and phenolic compound levels, which present high antioxidant effects, beneficial for the maintenance of consumer’s health. Argentina is the second largest strawberry producer in The Common Market of the Southern Cone (MERCOSUR), covering the main export destinations of Argentinian strawberries, i.e., Canada, United States, and European Union. Information about the bioactive compound occurrence and antioxidant capacity of these fruits is scarce or not available. Health related compounds of strawberry cultivars (Camarosa and Selva) from different zones of Argentina were investigated. Vitamin C content was in the same range for both studied cultivars. However, Camarosa strawberries, which are the most cultivated, consumed, and exported berries in Argentina, presented higher total phenolic and anthocyanins content, and consequently better in vitro antioxidant capacity. Moreover, there were differences in the occurrence and concentration in the phenolic compound profiles for both cultivars. Camarosa cultivar presented higher content of anthocyanidins, and Selva showed higher total ellagic acid content. The research shows that Argentina’s strawberries are an interesting source of bioactive compounds comparable to those in other parts of the world.
Teleconnections between tropical-extratropical oceans and the daily intensity of extreme rainfall over Argentina
Teleconnections between tropical-extratropical oceans and the daily intensity of extreme rainfall over Argentina
Robledo, Federico Ariel; Penalba, Olga Clorinda; Bettolli, Maria Laura
A Singular value decomposition (SVD) analysis was performed jointly on the daily intensity of extreme rainfall (DIER) over Argentina and the sea surface temperature (SST) of all the oceans from 17.5 °N to 90 °S in order to identify the large-scale variability of the SSTs related to extreme rainfall, in the period 1962–2005. The main objective of the article is to objectively recognize regions of the tropical and subtropical oceans that could be related with the extreme rainfall over Argentina. Spring is the season that is best represented by the first mode, accounting for up to 45% of the covariance between the DIER and SST. The first SVD mode of spring, summer and autumn presents a pattern of SST relating to the El Nino-Southern Oscillations (ENSO) phenomena with an enhanced DIER in different zones of centre and ˜ east of Argentina. In the second SVD mode of spring and summer, the SST patterns show cold conditions in the tropical and subtropical Atlantic and near Indonesia with an enhancement of the DIER in the centre and east of Argentina. These modes show a significant decadal variability. In the third SVD mode of spring and summer, the SST patterns present warm and cold conditions in the Indian Ocean and the centre and western Pacific Ocean (PO) with decreased rainfall in the northern and eastern portion of Argentina, respectively. This mode shows a significant period of temporal variability of around 14 years. The third mode of autumn presents warm conditions in the tropical Atlantic and the southwest PO with a low DIER in the centre and east of Argentina. This mode also presents temporal variability of around 14 years. The correlation between each mode derived from analysis of SVD and climate indices related with SST were computed.
Effect of Butternut (Cucurbita moschata Duchesne ex Poiret) Fibres on Bread Making, Quality and Staling
Effect of Butternut (Cucurbita moschata Duchesne ex Poiret) Fibres on Bread Making, Quality and Staling
de Escalada Pla, Marina Francisca; Rojas, Ana Maria Luisa; Gerschenson, Lia Noemi
The effect of different enriched fibre products obtained from butternut (Cucurbita moschata Duchesne ex Poiret) on bread making and bread quality was evaluated through the study of bread yield, quality parameters (specific volume, crumb firmness, crumb and crust colour) and bread shelf life. Fractions tested were obtained from butternut mesocarp through ethanolic treatment (fraction AIR) or through dehydration (fraction S) or from the ethanolic treatment of peel (fraction C). These fractions were incorporated in a bread formula, at levels of 5, 10 and 15 g of fibre fraction per kilogram of wheat flour. The study of crumb through digital imaging and thermal analysis was also performed in order to better understand the effects observed. An important influence of water absorption kinetics and chemical composition of the fibre fractions studied was observed in the results obtained. Lower bread firmness was determined 24 h after baking when 10 g of C or either 10 or 15 g of S was present per kilogram of wheat flour used. Breads made with flour containing 10–15 g of S or 5 g of C per kilogram of wheat flour tended to be softer, while 10 g of C per kilogram of flour produced significantly softer breads along 9 days storage.
Inter-annual and inter-decadal variability of dry days in Argentina
Inter-annual and inter-decadal variability of dry days in Argentina
Rivera, Juan Antonio; Penalba, Olga Clorinda; Bettolli, Maria Laura
This work proposes to employ the number of dry days (days without precipitation) as a variable of study, and to analyse their spatial and temporal variability in Argentina. Climatological aspects of dry days, such as their annual mean values and its seasonal cycle, were discussed and compared with precipitation features in the country. Linear trends in the annual number of dry days (ANDD) were identified for the period 1960–2005. Most of the regions exhibited decreasing trends, but few stations showed significant ones. The most important trends were present in the Central-West region and over the Patagonian coast and their magnitudes indicated a decrease of two to six dry days per decade. These trends coincide with the observed increase of accumulated precipitation in part of the country during the second half of the 20th century. To identify long-term fluctuations in the ANDD, a low pass filter, a wavelet analysis and a cubic polynomial fit was applied to the longest time series of the selected locations. Through these methodologies, periodicities were identified in the inter-annual and inter-decadal ranges for the last 80 years. The most important significant cycles were observed in the range of 10–24 years, but also, depending on the region, significant inter-annual variations were found.
P-Glycoprotein contributes to cell membrane depolarization of hippocampus and neocortex in a model of repetitive seizures induced by pentylenetetrazole in rats
P-Glycoprotein contributes to cell membrane depolarization of hippocampus and neocortex in a model of repetitive seizures induced by pentylenetetrazole in rats
Auzmendi, Jerónimo Andrés; Orozco Suárez, Sandra; Bañuelos Cabrera, Ivette; González Trujano, Maria Eva; Calixto Gonzàlez, Eduardo; Rocha, Luis; Lazarowski, Alberto
P-glycoprotein (P-gp) has been associated with pharmacoresistance and mechanisms regulating the membrane potential. However, at present it is unknown if P-gp overexpression in brain is associated with changes in membrane depolarization in refractory epilepsy. Experiments were designed to evaluate the membrane depolarization and P-gp overexpression induced by repetitive pentilenetetrazole (PTZ)-induced-seizures. Wistar rats were daily treated with PTZ during 4 to 7 days (PTZ4 and PTZ7 groups), and the brain was used to evaluate membrane potential by in vitro electrophysiological procedures and using bis-oxonol dye, [bis-(1,3-dibutylbarbituric acid) trimethine oxonol (DiBAC4(3)], a fluorescence dye voltage-sensitive to membrane potentials. Rats with repetitive PTZ-induced seizures demonstrated lower phenytoin-induced anticonvulsant effects, increased number of DiBAC4(3) fluorescence cells and P-gp overexpression in hippocampus and neocortex, as well as augmentation of the induced fEPSP in CA1 field. These changes were more evident in PTZ7 group. Phenytoin or phenytoin plus nimodipine (a P-gp antagonist) avoided the enhanced fEPSP and decreased DiBAC4(3) fluorescence in animals from PTZ4 group. However, in PTZ7 group these effects were evident only when phenytoin was combined with nimodipine. An additional flow cytometry study demonstrated increased intracellular accumulation of DiBAC4(3) in K562 leukemic cells that overexpress MDR-1 and COX-2 genes, and are refractory to specific cytotoxic agents. These results represent the first evidence supporting the notion that brain P-gp overexpression contributes to a progressive seizure-related membranes depolarization in hippocampus and neocortex. Further experiments should be carried out to confirm the role of P-gp on membrane depolarization and epileptogenesis process.
Hydrogen peroxide detection under physiological conditions by Prussian blue stabilized using a polyelectrolyte-surfactant complex matrix
Hydrogen peroxide detection under physiological conditions by Prussian blue stabilized using a polyelectrolyte-surfactant complex matrix
Gaviglio, Carina del Valle; Battaglini, Fernando
Poly(allylamine)–dodecylsulfate complex (PA–DS) is able to form a stable and layered structure onto graphite electrodes and can efficiently retain negatively charged ions like ferrocyanide. In this con- text, Prussian blue (PB) is electrochemically synthesized from a solution containing K3[Fe(CN)6] and FeCl3 at pH 1.7. The electrochemical behavior of the new system is investigated in different supporting electrolytes (K+ and Na+ ) and in acid and neutral media. Remarkable, well-defined and reversible voltam- metric responses are obtained, especially under physiological conditions (neutral pH and 150 mM NaCl). In these conditions, the modified electrode is able to electrocatalyze the reduction of hydrogen peroxide (H2O2) at micromolar levels, with a low detection limit and good sensitivity. These results represent an important improvement regarding further uses of PB in bioanalytical applications.
Phosphate Mediated Adsorption and Electron Transfer of Cytochrome C. A Time-Resolved SERR Spectroelectrochemical Study
Phosphate Mediated Adsorption and Electron Transfer of Cytochrome C. A Time-Resolved SERR Spectroelectrochemical Study
Capdevila, Daiana Andrea; Marmisollé, Waldemar Alejandro; Williams, Federico Jose; Murgida, Daniel Horacio
The study of proteins immobilized on biomimetic or biocompatible electrodes represents an active field of research as it pursues both fundamental and technological interests. In this context, adsorption and redox properties of cytochrome c (Cyt) on different electrode surfaces have been extensively reported, although in some cases with contradictory results. Here we report a SERR spectroelectrochemical study of the adsorption and electron transfer behaviour of the basic protein Cyt on electrodes coated with amino-terminated monolayers. The obtained results show that inorganic phosphate (Pi) and ATP anions are able to mediate high affinity binding of the protein with preservation of the native structure and rendering an average orientation that guarantees efficient pathways for direct electron transfer. These findings aid the design of Cyt-based bioelectronic devices and understanding the modulation by Pi and ATP of physiological functions of Cyt.
Linoleic acid stimulates neutral lipid accumulation in lipid droplets of maturing bovine oocytes
Linoleic acid stimulates neutral lipid accumulation in lipid droplets of maturing bovine oocytes
Carro, Maria de Las Mercedes; Buschiazzo, Jorgelina; Rios, Glenda Laura; Oresti, Gerardo Martin; Alberio, R. H.
Linoleic acid (LA) is a polyunsaturated fatty acid present in high concentrations in bovine follicular fluid; when added to maturation culture media, it affects oocyte competence (depending on the type and concentration of LA used). To date, little is known about the effective level of incorporation of LA and there is apparently no information regarding its esterification into various lipid fractions of the oocyte and its effect on neutral lipid storage. Therefore, the objective was to assess the uptake and subcellular lipid distribution of LA by analyzing incorporation of radiolabeled LA into oocyte polar and neutral lipid classes. The effects of various concentrations of LA on the nuclear status and cytoplasmic lipid content of bovine oocytes matured in vitro was also analyzed, with particular emphasis on intermediate concentrations of LA. Neutral lipids stored in lipid droplets were quantified with a fluorescence approach. Linoleic acid at 9 and 43 μM did not affect the nuclear status of oocytes matured in vitro, and 100 μM LA inhibited germinal vesicle breakdown, resulting in a higher percentage of oocytes arrested at the germinal state (43.5 vs. 3.0 in controls; P < 0.05). Bovine oocytes actively incorporated LA from the maturation medium (83.4 pmol LA per 100 oocytes at 22 hours of incubation; P < 0.05) and metabolized it mainly into major lipid classes, e.g., triacylglycerols and phospholipids (61.1% and 29.3%, respectively). Supplementation of the maturation medium with LA increased triacylglycerol accumulation in cytoplasmic lipid droplets at all concentrations assayed (P < 0.05). In conclusion, LA added to a defined maturation medium at concentrations that did not alter the nuclear status of bovine oocytes matured in vitro (9 and 43 μM) improved their quality by increasing the content of neutral lipids stored in lipid droplets. By directing the free fatty acid (LA) to triacylglycerol synthesis pathways and increasing the degree of unsaturation of membrane phospholipids, the oocyte was protected from lipotoxic effects (with an expectation of improved cryotolerance).
Spectroscopic Characterization and Constitutional and Rotational Isomerism of ClC(O)SCN and ClC(O)NCS
Spectroscopic Characterization and Constitutional and Rotational Isomerism of ClC(O)SCN and ClC(O)NCS
Ramos, Luis A.; Ulic, Sonia Elizabeth; Romano, Rosana Mariel; Erben, Mauricio Federico; Vishnevskiy, Yuri V.; Reuter, Christian G.; Mitzel, Norbert W.; Beckers, Helmut; Willner, Helge; Zeng, Xiaoqing; Bernhardt, Eduard; Ge, Maofa; Tong, Shengrui; Della Védova, Carlos Omar
Chlorocarbonylthio- and isothiocyanate (ClC(O)SCN and ClC(O)- NCS) have been isolated and characterized by IR (Ar matrix, gas), Raman (liquid), 13C NMR and UV−visible spectroscopies. Vibrational and quantum chemical studies suggest the presence of the syn and anti conformers (SCN group with respect to the CO bond) in the gas phase for both constitutional isomers. syn-ClC(O)SCN is preferred by ΔH° (anti/syn) = 1.3(0.3) kcal mol−1 . The solid-state structure of ClC(O)SCN has been determined by single crystal X-ray diffraction analysis at low temperature. The crystalline solid consists exclusively of molecules in the syn conformation. On the other hand, the anti form is more stable for the ClC(O)NCS isomer. The structure of ClC(O)NCS and its conformational composition were determined by gas electron diffraction. An unusual low syn → anti interconversion energy barrier of 0.98 (0.15) kcal mol−1 was detected for ClC(O)NCS at cryogenic temperatures. The photochemistry of both constitutional isomers isolated in solid argon at 15 K was studied. Rearrangement of ClC(O)SCN to ClC(O)NCS was observed in the neat liquid and under UV−vis irradiation of ClC(O)SCN isolated in solid argon. Properties have been discussed in terms of the valence electronic structure, including the analysis of the He(I) photoelectron spectrum of ClC(O)SCN
Targeting of insect epicuticular lipids by entomopathogenic fungi: hydrocarbon oxidation within the context of a host-pathogen interaction
Targeting of insect epicuticular lipids by entomopathogenic fungi: hydrocarbon oxidation within the context of a host-pathogen interaction
Pedrini, Nicolás; Ortiz Urquiza, Almudena; Huarte Bonnet, Carla; Zhang, Shizhu; Keyhani, Nemat O.
Broad host range entomopathogenic fungi such as Beauveria bassiana attack insect hosts via attachment to cuticular substrata and the production of enzymes for the degradation and penetration of insect cuticle. The outermost epicuticular layer consists of a complex mixture of non-polar lipids including hydrocarbons, fatty acids, and wax esters. Long chain hydrocarbons are major components of the outer waxy layer of diverse insect species, where they serve to protect against desiccation and microbial parasites, and as recognition molecules or as a platform for semiochemicals. Insect pathogenic fungi have evolved mechanisms for overcoming this barrier, likely with sets of lipid degrading enzymes with overlapping substrate specificities. Alkanes and fatty acids are substrates for a specific subset of fungal cytochrome P450 monooxygenases involved in insect hydrocarbon degradation. These enzymes activate alkanes by terminal oxidation to alcohols, which are further oxidized by alcohol and aldehyde dehydrogenases, whose products can enter β-oxidation pathways. B. bassiana contains at least 83 genes coding for cytochrome P450s (CYP), a subset of which are involved in hydrocarbon oxidation, and several of which represent new CYP subfamilies/families. Expression data indicated differential induction by alkanes and insect lipids and four CYP proteins have been partially characterized after heterologous expression in yeast. Gene knockouts revealed a phenotype for only one (cyp52X1) out of six genes examined to date. CYP52X1 oxidizes long chain fatty acids and participates in the degradation of specific epicuticular lipid components needed for breaching the insect waxy layer. Examining the hydrocarbon oxidizing CYP repertoire of pathogens involved in insect epicuticle degradation can lead to the characterization of enzymes with novel substrate specificities. Pathogen targeting may also represent an important co-evolutionary process regarding insect cuticular hydrocarbon synthesis.
Changes in secondary structure of gluten proteins due to emulsifiers
Changes in secondary structure of gluten proteins due to emulsifiers
Gómez, Analía Verónica; Ferrer, Evelina Gloria; Añon, Maria Cristina; Puppo, Maria Cecilia
Changes in the secondary structure of gluten proteins due to emulsifiers were analyzed by Raman Spectroscopy. The protein folding induced by 0.25% SSL (Sodium Stearoyl Lactylate) (GS0.25, Gluten + 0.25% SSL) included an increase in alfa-helix conformation and a decrease in beta-sheet, turns and random coil. The same behavior, although in a less degree, was observed for 0.5% gluten?DATEM (Diacetyl Tartaric Acid Esters of Monoglycerides) system. The low burial of Tryptophan residues to a more hydrophobic environment and the low percentage area of the C?H stretching band for GS0.25 (Gluten + 0.25% SSL), could be related to the increased in a-helix conformation. This behavior was also confirmed by changes in stretching vibrational modes of disulfide bridges (S?S) and the low exposure of Tyrosine residues. High levels of SSL (0.5% and 1.0%) and DATEM (1.0%) led to more disordered protein structures, with different gluten networks. SSL (1.0%) formed a more disordered and opened gluten matrix than DATEM, the last one being laminar and homogeneous.
Sequencing of two Sunflower chlorotic mottle virus isolates obtained from different natural hosts shed light on its evolutionary history
Sequencing of two Sunflower chlorotic mottle virus isolates obtained from different natural hosts shed light on its evolutionary history
Bejerman, Nicolas; Giolitti, Fabián José; de Breuil, Soledad; Lenardon, Sergio Luis
Sunflower chlorotic mottle virus (SuCMoV), the most prevalent virus of sunflower in Argentina, was reported naturally infecting not only sunflower but also weeds. To understand SuCMoV evolution and improve the knowledge on its variability, the complete genomic sequences of two SuCMoV isolates collected from Dipsacus fullonum (-dip) and Ibicella lutea (-ibi) were determined from three overlapping cDNA clones and subjected to phylogenetic and recombination analyses. SuCMoV-dip and -ibi genomes were 9,953-nucleotides (nt) long; their sequences contained an open reading frame of 9,561 nucleotides, which encoded a polyprotein of 3,187 amino acids flanked by a 5′-noncoding region (NCR) of 135 nt and a 3′-NCR of 257 nt. SuCMoV-dip and -ibi genome nucleotide sequences were 90.9 identical and displayed 90 and 94.6 % identity to that of SuCMoV-C, and 90.8 and 91.4 % identity to that of SuCMoV-CRS, respectively. P1 of SuCMoV-dip and -ibi was 3-nt longer than that of SuCMoV-CRS, but 12-nt shorter than that of SuCMoV-C. Two recombination events were detected in SuCMoV genome and the analysis of dN/dS ratio among SuCMoV complete sequences showed that the genomic regions are under different evolutionary constraints, suggesting that SuCMoV evolution would be conservative. Our findings provide evidence that mutation and recombination would have played important roles in the evolutionary history of SuCMoV.
Search for supersymmetry in events with photons, bottom quarks, and missing transverse momentum in proton-proton collisions at a centre-of-mass energy of 7 TeV with the ATLAS detector
Search for supersymmetry in events with photons, bottom quarks, and missing transverse momentum in proton-proton collisions at a centre-of-mass energy of 7 TeV with the ATLAS detector
Aad, G.; Abbott, B.; Abdallah, J.; Abdel Khalek, S.; Abdelalim, A.A.; González Silva, María Laura; Otero y Garzon, Gustavo Javier; Piegaia, Ricardo Nestor; Romeo, Gaston Leonardo; Anduaga, Xabier Sebastian; Dova, Maria Teresa; Monticelli, Fernando Gabriel; Tripiana, Martin Fernando; Zhu, Y.; Zhuang, X. .; Zhuravlov, V.; Zieminska, D.; Zimine, N. I.; Zimmermann, R.; Zimmermann, C.; Zimmermann, S.; Ziolkowski, M.; Zitoun, R.; Živković, L.; Zmouchko, V. V.; Zobernig, G.; Zoccoli, A.; Nedden, M. zur; Zutshi, V.; Zwalinski, L.; The ATLAS Collaboration
The integrated and differential fiducial cross sections for the production of a W or Z boson in association with a high-energy photon are measured using pp collisions at ffiffi s p ¼ 7 TeV. The analyses use a data sample with an integrated luminosity of 4:6 fb 1 collected by the ATLAS detector during the 2011 LHC data-taking period. Events are selected using leptonic decays of the W and Z bosons [Wðe ; Þ and Zðeþe ; þ ; Þ] with the requirement of an associated isolated photon. The data are used to test the electroweak sector of the Standard Model and search for evidence for new phenomena. The measurements are used to probe the anomalous WW, ZZ, and Z triple-gauge-boson couplings and to search for the production of vector resonances decaying to Z and W. No deviations from Standard Model predictions are observed and limits are placed on anomalous triple-gauge-boson couplings and on the production of new vector meson resonances.
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